Mr. Arafat says he is making a real effort to crack down on militant groups, but Palestinian officials say he cannot be expected to carry out large scale arrests while Israeli soldiers are raiding Palestinian areas.

Israeli troops and tanks remain in Jenin and Tulkarm, two of the six West Bank towns seized after Palestinian gunmen assassinated an Israeli cabinet minister last month.

On Wednesday Israeli forces pulled out of Ramallah, the West Bank headquarters of the Palestinian Authority, but continue to maintain a tight blockade around the city.

Palestinian Information Minister Yasser Abed Rabbo says because of the continuing closures around the West Bank and Gaza, the Palestinians remain under siege.

"The Israeli occupation forces impose the strictest measures in order to continue the siege all around the city and all around other cities and villages," Mr. Rabbo said.

Israeli government spokesman Dore Gold says the military reserves the right to launch new incursions if the Palestinians do not maintain security in the territory they control.

"Should our security situation deteriorate, Israel has the full right to do what is necessary to defend its citizens from the attacks coming from Mr. Arafat's cities," Mr. Gold said.

The United States has been urging Israel to pull its soldiers out of all areas under Palestinian control.

The incursions were the largest Israeli military operation in the West Bank since the Jewish state began handing over territory to the Palestinians under interim peace accords in 1994.